YASMIN is a project focused on implementing robot behaviors using Finite State Machines (FSM). It is available for ROS 2, Python and C++.

ROS 2 Distro	Build and Test	Docker Image
Foxy
Galatic
Humble
Iron
Jazzy
Kilted
Rolling

Key Features

ROS 2 Integration: Integrates with ROS 2 for easy deployment and interaction.
Support for Python and C++: Available for both Python and C++, making it flexible for a variety of use cases.
Rapid Prototyping: Designed for fast prototyping, allowing quick iteration of state machine behaviors.
Predefined States: Includes states for interacting with ROS 2 action clients, service clients, and topics.
Data Sharing with Blackboards: Utilizes blackboards for data sharing between states and state machines.
State Management: Supports cancellation and stopping of state machines, including halting the current executing state.
Web Viewer: Features an integrated web viewer for real-time monitoring of state machine execution.

Installation

Debian Packages

To install YASMIN and its packages, use the following command:

sudo apt install ros-$ROS_DISTRO-yasmin ros-$ROS_DISTRO-yasmin-*

Building from Source

Follow these steps to build the source code from this repository:

cd ~/ros2_ws/src
git clone https://github.com/uleroboticsgroup/yasmin.git
cd ~/ros2_ws
rosdep install --from-paths src --ignore-src -r -y
cd ~/ros2_ws
colcon build

Then, you can run the tests as follow:

colcon test --packages-select yasmin yasmin_ros yasmin_factory

colcon test-result --verbose

Docker

If your operating system doesn't support ROS 2, docker is a great alternative. You can use an image from Dockerhub or create your own images. First of all, to build the image you have to use the following command:

## Assuming you are in the YASMIN project directory

docker build -t yasmin .

To use a shortcut the docker build, you may use the following command:

## Assuming you are in the YASMIN project directory

make docker_build

After the image is created, run a docker container with the following command:

docker run -it --net=host --ipc=host --privileged --env="DISPLAY" --env="QT_X11_NO_MITSHM=1" --volume="/tmp/.X11-unix:/tmp/.X11-unix:rw" --volume="${XAUTHORITY}:/root/.Xauthority" --entrypoint /bin/bash yasmin

To use a shortcut the docker run, you may use following command:

## Assuming you are in the YASMIN project directory

make docker_run

Demos

There are some examples, for both Python and C++, that can be found in yasmin_demos.

Python

Vanilla Demo (FSM)

Click to expand

ros2 run yasmin_demos yasmin_demo.py

import time
import rclpy
 
import yasmin
from yasmin import State, Blackboard, StateMachine
from yasmin_ros import set_ros_loggers
from yasmin_viewer import YasminViewerPub
 
 
# Define the FooState class, inheriting from the State class
class FooState(State):
    """
    Represents the Foo state in the state machine.
 
    Attributes:
        counter (int): Counter to track the number of executions of this state.
    """
 
    def __init__(self) -> None:
        """
        Initializes the FooState instance, setting up the outcomes.
 
        Outcomes:
            outcome1: Indicates the state should continue to the Bar state.
            outcome2: Indicates the state should finish execution and return.
        """
        super().__init__(["outcome1", "outcome2"])
        self.counter = 0
 
    def execute(self, blackboard: Blackboard) -> str:
        """
        Executes the logic for the Foo state.
 
        Args:
            blackboard (Blackboard): The shared data structure for states.
 
        Returns:
            str: The outcome of the execution, which can be "outcome1" or "outcome2".
 
        Raises:
            Exception: May raise exceptions related to state execution.
        """
        yasmin.YASMIN_LOG_INFO("Executing state FOO")
        time.sleep(3)  # Simulate work by sleeping
 
        if self.counter < 3:
            self.counter += 1
            blackboard["foo_str"] = f"Counter: {self.counter}"
            return "outcome1"
        else:
            return "outcome2"
 
 
# Define the BarState class, inheriting from the State class
class BarState(State):
    """
    Represents the Bar state in the state machine.
    """
 
    def __init__(self) -> None:
        """
        Initializes the BarState instance, setting up the outcome.
 
        Outcomes:
            outcome3: Indicates the state should transition back to the Foo state.
        """
        super().__init__(outcomes=["outcome3"])
 
    def execute(self, blackboard: Blackboard) -> str:
        """
        Executes the logic for the Bar state.
 
        Args:
            blackboard (Blackboard): The shared data structure for states.
 
        Returns:
            str: The outcome of the execution, which will always be "outcome3".
 
        Raises:
            Exception: May raise exceptions related to state execution.
        """
        yasmin.YASMIN_LOG_INFO("Executing state BAR")
        time.sleep(3)  # Simulate work by sleeping
 
        yasmin.YASMIN_LOG_INFO(blackboard["foo_str"])
        return "outcome3"
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("yasmin_demo")
 
    # Initialize ROS 2
    rclpy.init()
 
    # Set ROS 2 loggers
    set_ros_loggers()
 
    # Create a finite state machine (FSM)
    sm = StateMachine(outcomes=["outcome4"])
 
    # Add states to the FSM
    sm.add_state(
        "FOO",
        FooState(),
        transitions={
            "outcome1": "BAR",
            "outcome2": "outcome4",
        },
    )
    sm.add_state(
        "BAR",
        BarState(),
        transitions={
            "outcome3": "FOO",
        },
    )
 
    # Publish FSM information for visualization
    viewer = YasminViewerPub(sm, "YASMIN_DEMO")
 
    # Execute the FSM
    try:
        outcome = sm()
        yasmin.YASMIN_LOG_INFO(outcome)
    except KeyboardInterrupt:
        if sm.is_running():
            sm.cancel_state()
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
 
if __name__ == "__main__":
    main()

Blackboard Remapping Demo

Click to expand

ros2 run yasmin_demos remap_demo.py

import rclpy
 
import yasmin
from yasmin import State, Blackboard, StateMachine
from yasmin_ros import set_ros_loggers
from yasmin_ros.basic_outcomes import SUCCEED
from yasmin_viewer import YasminViewerPub
 
 
class Foo(State):
    """
    Represents the Foo state in the state machine.
    """
 
    def __init__(self):
        """
        Initializes the FooState instance, setting up the outcomes.
 
        Outcomes:
            SUCCEED: Indicates the state should continue to the next state.
        """
        super().__init__(outcomes=[SUCCEED])
 
    def execute(self, blackboard: Blackboard):
        """
        Executes the logic for the Foo state.
 
        Args:
            blackboard (Blackboard): The shared data structure for states.
 
        Returns:
            str: The outcome of the execution, which can be SUCCEED.
 
        Raises:
            Exception: May raise exceptions related to state execution.
        """
        data = blackboard["foo_data"]
        yasmin.YASMIN_LOG_INFO(f"{data}")
        blackboard["foo_out_data"] = data
        return SUCCEED
 
 
class BarState(State):
    """
    Represents the Bar state in the state machine.
 
    """
 
    def __init__(self):
        """
        Initializes the BarState instance, setting up the outcomes.
 
        Outcomes:
            SUCCEDED: Indicates the state should continue to the next state.
        """
        super().__init__(outcomes=[SUCCEED])
 
    def execute(self, blackboard: Blackboard):
        """
        Executes the logic for the Bar state.
 
        Args:
            blackboard (Blackboard): The shared data structure for states.
 
        Returns:
            str: The outcome of the execution, which can be SUCCEED.
 
        Raises:
            Exception: May raise exceptions related to state execution.
        """
        data = blackboard["bar_data"]
        yasmin.YASMIN_LOG_INFO(f"{data}")
        return SUCCEED
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("yasmin_remapping_demo")
    rclpy.init()
    set_ros_loggers()
 
    bb = Blackboard()
    bb["msg1"] = "test1"
    bb["msg2"] = "test2"
 
    sm = StateMachine(outcomes=[SUCCEED])
    sm.add_state(
        "STATE1",
        Foo(),
        transitions={SUCCEED: "STATE2"},
        remappings={"foo_data": "msg1"},
    )
    sm.add_state(
        "STATE2",
        Foo(),
        transitions={SUCCEED: "STATE3"},
        remappings={"foo_data": "msg2"},
    )
    sm.add_state(
        "STATE3",
        BarState(),
        transitions={SUCCEED: SUCCEED},
        remappings={"bar_data": "foo_out_data"},
    )
 
    # Launch YASMIN Viewer publisher for state visualization
    viewer = YasminViewerPub(sm, "YASMIN_REMAPPING_DEMO")
 
    # Execute the FSM
    try:
        outcome = sm(bb)
        yasmin.YASMIN_LOG_INFO(outcome)
    except KeyboardInterrupt:
        if sm.is_running():
            sm.cancel_state()
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
 
if __name__ == "__main__":
    main()

Concurrence Demo

Click to expand

ros2 run yasmin_demos concurrence_demo.py

import time
import rclpy
 
import yasmin
from yasmin import State, Concurrence, Blackboard, StateMachine
from yasmin_ros import set_ros_loggers
from yasmin_viewer import YasminViewerPub
 
 
# Define the FooState class, inheriting from the State class
class FooState(State):
    """
    Represents the Foo state in the state machine.
 
    Attributes:
        counter (int): Counter to track the number of executions of this state.
    """
 
    def __init__(self) -> None:
        """
        Initializes the FooState instance, setting up the outcomes.
 
        Outcomes:
            outcome1: Indicates the state should continue.
            outcome2: Indicates the state should cotninue.
            outcome3: Indicates the state should finish execution and return.
        """
        super().__init__(["outcome1", "outcome2", "outcome3"])
        self.counter = 0
 
    def execute(self, blackboard: Blackboard) -> str:
        """
        Executes the logic for the Foo state.
 
        Args:
            blackboard (Blackboard): The shared data structure for states.
 
        Returns:
            str: The outcome of the execution.
 
        Raises:
            Exception: May raise exceptions related to state execution.
        """
        yasmin.YASMIN_LOG_INFO("Executing state FOO")
        time.sleep(2)  # Simulate work by sleeping
 
        outcome = ""
 
        blackboard["foo_str"] = f"Counter: {self.counter}"
 
        if self.counter < 3:
            outcome = "outcome1"
        elif self.counter < 5:
            outcome = "outcome2"
        else:
            outcome = "outcome3"
 
        yasmin.YASMIN_LOG_INFO("Finishing state FOO")
        self.counter += 1
        return outcome
 
 
# Define the BarState class, inheriting from the State class
class BarState(State):
    """
    Represents the Bar state in the state machine.
    """
 
    def __init__(self) -> None:
        """
        Initializes the BarState instance, setting up the outcome.
 
        Outcomes:
            outcome3: This state will always return this outcome
        """
        super().__init__(outcomes=["outcome3"])
 
    def execute(self, blackboard: Blackboard) -> str:
        """
        Executes the logic for the Bar state.
 
        Args:
            blackboard (Blackboard): The shared data structure for states.
 
        Returns:
            str: The outcome of the execution, which will always be "outcome3".
 
        Raises:
            Exception: May raise exceptions related to state execution.
        """
        yasmin.YASMIN_LOG_INFO("Executing state BAR")
        time.sleep(4)  # Simulate work by sleeping
 
        if "foo_str" in blackboard:
            yasmin.YASMIN_LOG_INFO(blackboard["foo_str"])
        else:
            yasmin.YASMIN_LOG_INFO("Blackboard does not yet contain 'foo_str'")
 
        yasmin.YASMIN_LOG_INFO("Finishing state BAR")
 
        return "outcome3"
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("CONCURRENCE_DEMO")
 
    # Initialize ROS 2
    rclpy.init()
 
    # Set ROS 2 loggers
    set_ros_loggers()
 
    # Create a finite state machine (FSM)
    sm = StateMachine(outcomes=["outcome4"])
 
    # Create states to run concurrently
    foo_state: State = FooState()
    bar_state: State = BarState()
 
    # Add concurrence state
    concurrence_state = Concurrence(
        states={
            "FOO": foo_state,
            "BAR": bar_state,
        },
        default_outcome="defaulted",
        outcome_map={
            "outcome1": {
                "FOO": "outcome1",
                "BAR": "outcome3",
            },
            "outcome2": {
                "FOO": "outcome2",
                "BAR": "outcome3",
            },
        },
    )
 
    # Add concurrent state to the FSM
    sm.add_state(
        "CONCURRENCE",
        concurrence_state,
        transitions={
            "outcome1": "CONCURRENCE",
            "outcome2": "CONCURRENCE",
            "defaulted": "outcome4",
        },
    )
 
    # Publish FSM information for visualization
    viewer = YasminViewerPub(sm, "YASMIN_CONCURRENCE_DEMO")
 
    # Execute the FSM
    try:
        outcome = sm()
        yasmin.YASMIN_LOG_INFO(outcome)
    except KeyboardInterrupt:
        if sm.is_running():
            sm.cancel_state()
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
 
if __name__ == "__main__":
    main()

Service Demo (FSM + ROS 2 Service Client)

Click to expand

ros2 run yasmin_demos add_two_ints_server

ros2 run yasmin_demos service_client_demo.py

import rclpy
from example_interfaces.srv import AddTwoInts
 
import yasmin
from yasmin import CbState, Blackboard, StateMachine
from yasmin_ros import ServiceState
from yasmin_ros import set_ros_loggers
from yasmin_ros.basic_outcomes import SUCCEED, ABORT
from yasmin_viewer import YasminViewerPub
 
 
class AddTwoIntsState(ServiceState):
    """
    A state that calls the AddTwoInts service to add two integers.
 
    This class is a state in a finite state machine that sends a request
    to the AddTwoInts service, retrieves the response, and updates the
    blackboard with the result.
 
    Attributes:
        service_type (type): The service type being used (AddTwoInts).
        service_name (str): The name of the service.
        outcomes (list): The list of possible outcomes for this state.
    """
 
    def __init__(self) -> None:
        """
        Initializes the AddTwoIntsState.
 
        Calls the parent constructor with the specific service type,
        service name, request handler, outcomes, and response handler.
        """
        super().__init__(
            AddTwoInts,  # srv type
            "/add_two_ints",  # service name
            self.create_request_handler,  # cb to create the request
            ["outcome1"],  # outcomes. Includes (SUCCEED, ABORT)
            self.response_handler,  # cb to process the response
        )
 
    def create_request_handler(self, blackboard: Blackboard) -> AddTwoInts.Request:
        """
        Creates the service request from the blackboard data.
 
        Args:
            blackboard (Blackboard): The blackboard containing the input values.
 
        Returns:
            AddTwoInts.Request: The request object populated with values from the blackboard.
        """
        req = AddTwoInts.Request()
        req.a = blackboard["a"]
        req.b = blackboard["b"]
        return req
 
    def response_handler(
        self, blackboard: Blackboard, response: AddTwoInts.Response
    ) -> str:
        """
        Processes the response from the AddTwoInts service.
 
        Updates the blackboard with the sum result from the response.
 
        Args:
            blackboard (Blackboard): The blackboard to update with the sum.
            response (AddTwoInts.Response): The response from the service call.
 
        Returns:
            str: The outcome of the operation, which is "outcome1".
        """
        blackboard["sum"] = response.sum
        return "outcome1"
 
 
def set_ints(blackboard: Blackboard) -> str:
    """
    Sets the integer values in the blackboard.
 
    This function initializes the blackboard with two integer values to be added.
 
    Args:
        blackboard (Blackboard): The blackboard to update with integer values.
 
    Returns:
        str: The outcome of the operation, which is SUCCEED.
    """
    blackboard["a"] = 10
    blackboard["b"] = 5
    return SUCCEED
 
 
def print_sum(blackboard: Blackboard) -> str:
    """
    Logs the sum value from the blackboard.
 
    This function retrieves the sum from the blackboard and logs it.
 
    Args:
        blackboard (Blackboard): The blackboard from which to retrieve the sum.
 
    Returns:
        str: The outcome of the operation, which is SUCCEED.
    """
    yasmin.YASMIN_LOG_INFO(f"Sum: {blackboard['sum']}")
    return SUCCEED
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("yasmin_service_client_demo")
 
    # Init ROS 2
    rclpy.init()
 
    # Set ROS 2 logs
    set_ros_loggers()
 
    # Create a FSM
    sm = StateMachine(outcomes=["outcome4"])
 
    # Add states
    sm.add_state(
        "SETTING_INTS",
        CbState([SUCCEED], set_ints),
        transitions={SUCCEED: "ADD_TWO_INTS"},
    )
    sm.add_state(
        "ADD_TWO_INTS",
        AddTwoIntsState(),
        transitions={
            "outcome1": "PRINTING_SUM",
            SUCCEED: "outcome4",
            ABORT: "outcome4",
        },
    )
    sm.add_state(
        "PRINTING_SUM",
        CbState([SUCCEED], print_sum),
        transitions={
            SUCCEED: "outcome4",
        },
    )
 
    # Publish FSM info
    viewer = YasminViewerPub(sm, "YASMIN_SERVICE_CLIENT_DEMO")
 
    # Execute FSM
    try:
        outcome = sm()
        yasmin.YASMIN_LOG_INFO(outcome)
    except KeyboardInterrupt:
        if sm.is_running():
            sm.cancel_state()
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
 
if __name__ == "__main__":
    main()

Action Demo (FSM + ROS 2 Action)

Click to expand

ros2 run yasmin_demos fibonacci_action_server

ros2 run yasmin_demos action_client_demo.py

import rclpy
from example_interfaces.action import Fibonacci
 
import yasmin
from yasmin import CbState, Blackboard, StateMachine
from yasmin_ros import ActionState
from yasmin_ros import set_ros_loggers
from yasmin_ros.basic_outcomes import SUCCEED, ABORT, CANCEL
from yasmin_viewer import YasminViewerPub
 
 
class FibonacciState(ActionState):
    """
    Class representing the state of the Fibonacci action.
 
    Inherits from ActionState and implements methods to handle the
    Fibonacci action in a finite state machine.
 
    Attributes:
        None
    """
 
    def __init__(self) -> None:
        """
        Initializes the FibonacciState.
 
        Sets up the action type and the action name for the Fibonacci
        action. Initializes goal, response handler, and feedback
        processing callbacks.
 
        Args:
            None
 
        Returns:
            None
        """
        super().__init__(
            Fibonacci,  # action type
            "/fibonacci",  # action name
            self.create_goal_handler,  # callback to create the goal
            None,  # outcomes. Includes (SUCCEED, ABORT, CANCEL)
            self.response_handler,  # callback to process the response
            self.print_feedback,  # callback to process the feedback
        )
 
    def create_goal_handler(self, blackboard: Blackboard) -> Fibonacci.Goal:
        """
        Creates the goal for the Fibonacci action.
 
        This method retrieves the input value from the blackboard and
        populates the Fibonacci goal.
 
        Args:
            blackboard (Blackboard): The blackboard containing the state
            information.
 
        Returns:
            Fibonacci.Goal: The populated goal object for the Fibonacci action.
 
        Raises:
            KeyError: If the expected key is not present in the blackboard.
        """
        goal = Fibonacci.Goal()
        goal.order = blackboard["n"]  # Retrieve the input value 'n' from the blackboard
        return goal
 
    def response_handler(self, blackboard: Blackboard, response: Fibonacci.Result) -> str:
        """
        Handles the response from the Fibonacci action.
 
        This method processes the result of the Fibonacci action and
        stores it in the blackboard.
 
        Args:
            blackboard (Blackboard): The blackboard to store the result.
            response (Fibonacci.Result): The result object from the Fibonacci action.
 
        Returns:
            str: Outcome of the operation, typically SUCCEED.
 
        Raises:
            None
        """
        blackboard["fibo_res"] = (
            response.sequence
        )  # Store the result sequence in the blackboard
        return SUCCEED
 
    def print_feedback(
        self, blackboard: Blackboard, feedback: Fibonacci.Feedback
    ) -> None:
        """
        Prints feedback from the Fibonacci action.
 
        This method logs the partial sequence received during the action.
 
        Args:
            blackboard (Blackboard): The blackboard (not used in this method).
            feedback (Fibonacci.Feedback): The feedback object from the Fibonacci action.
 
        Returns:
            None
 
        Raises:
            None
        """
        yasmin.YASMIN_LOG_INFO(f"Received feedback: {list(feedback.sequence)}")
 
 
def print_result(blackboard: Blackboard) -> str:
    """
    Prints the result of the Fibonacci action.
 
    This function logs the final result stored in the blackboard.
 
    Args:
        blackboard (Blackboard): The blackboard containing the result.
 
    Returns:
        str: Outcome of the operation, typically SUCCEED.
 
    Raises:
        None
    """
    yasmin.YASMIN_LOG_INFO(f"Result: {blackboard['fibo_res']}")
    return SUCCEED
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("yasmin_action_client_demo")
 
    # Initialize ROS 2
    rclpy.init()
 
    # Set up ROS 2 logs
    set_ros_loggers()
 
    # Create a finite state machine (FSM)
    sm = StateMachine(outcomes=["outcome4"])
 
    # Add states to the FSM
    sm.add_state(
        "CALLING_FIBONACCI",
        FibonacciState(),
        transitions={
            SUCCEED: "PRINTING_RESULT",
            CANCEL: "outcome4",
            ABORT: "outcome4",
        },
    )
    sm.add_state(
        "PRINTING_RESULT",
        CbState([SUCCEED], print_result),
        transitions={
            SUCCEED: "outcome4",
        },
    )
 
    # Publish FSM information
    viewer = YasminViewerPub(sm, "YASMIN_ACTION_CLIENT_DEMO")
 
    # Create an initial blackboard with the input value
    blackboard = Blackboard()
    blackboard["n"] = 10  # Set the Fibonacci order to 10
 
    # Execute the FSM
    try:
        outcome = sm(blackboard)
        yasmin.YASMIN_LOG_INFO(outcome)
    except KeyboardInterrupt:
        if sm.is_running():
            sm.cancel_state()  # Cancel the state if interrupted
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
 
if __name__ == "__main__":
    main()

Monitor Demo (FSM + ROS 2 Subscriber)

Click to expand

ros2 run yasmin_demos monitor_demo.py

import rclpy
from rclpy.qos import qos_profile_sensor_data
from nav_msgs.msg import Odometry
 
import yasmin
from yasmin import Blackboard, StateMachine
from yasmin_ros import MonitorState
from yasmin_ros import set_ros_loggers
from yasmin_ros.basic_outcomes import TIMEOUT
from yasmin_viewer import YasminViewerPub
 
 
class PrintOdometryState(MonitorState):
    """
    MonitorState subclass to handle Odometry messages.
 
    This state monitors Odometry messages from the specified ROS topic,
    logging them and transitioning based on the number of messages received.
 
    Attributes:
        times (int): The number of messages to monitor before transitioning
                     to the next outcome.
 
    Args:
        times (int): The initial count of how many Odometry messages to
                     process before changing state.
 
    Methods:
        monitor_handler(blackboard: Blackboard, msg: Odometry) -> str:
            Handles incoming Odometry messages, logging the message and
            returning the appropriate outcome based on the remaining count.
    """
 
    def __init__(self, times: int) -> None:
        """
        Initializes the PrintOdometryState.
 
        Args:
            times (int): The number of Odometry messages to monitor before
                         transitioning to the next outcome.
        """
        super().__init__(
            Odometry,  # msg type
            "odom",  # topic name
            ["outcome1", "outcome2"],  # outcomes
            self.monitor_handler,  # monitor handler callback
            qos=qos_profile_sensor_data,  # qos for the topic subscription
            msg_queue=10,  # queue for the monitor handler callback
            timeout=10,  # timeout to wait for messages in seconds
        )
        self.times = times
 
    def monitor_handler(self, blackboard: Blackboard, msg: Odometry) -> str:
        """
        Handles incoming Odometry messages.
 
        This method is called whenever a new Odometry message is received.
        It logs the message, decrements the count of messages to process,
        and determines the next state outcome.
 
        Args:
            blackboard (Blackboard): The shared data storage for states.
            msg (Odometry): The incoming Odometry message.
 
        Returns:
            str: The next state outcome, either "outcome1" to continue
                 monitoring or "outcome2" to transition to the next state.
 
        Exceptions:
            None
        """
        yasmin.YASMIN_LOG_INFO(msg)
 
        self.times -= 1
 
        if self.times <= 0:
            return "outcome2"
 
        return "outcome1"
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("yasmin_monitor_demo")
 
    # Initialize ROS 2
    rclpy.init()
 
    # Set ROS 2 logs
    set_ros_loggers()
 
    # Create a finite state machine (FSM)
    sm = StateMachine(outcomes=["outcome4"])
 
    # Add states to the FSM
    sm.add_state(
        "PRINTING_ODOM",
        PrintOdometryState(5),
        transitions={
            "outcome1": "PRINTING_ODOM",
            "outcome2": "outcome4",
            TIMEOUT: "outcome4",
            CANCEL: "outcome4",
        },
    )
 
    # Publish FSM information
    viewer = YasminViewerPub(sm, "YASMIN_MONITOR_DEMO")
 
    # Execute FSM
    try:
        outcome = sm()
        yasmin.YASMIN_LOG_INFO(outcome)
    except KeyboardInterrupt:
        if sm.is_running():
            sm.cancel_state()
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
 
if __name__ == "__main__":
    main()

Publisher Demo (FSM + ROS 2 Publisher)

Click to expand

ros2 run yasmin_demos publisher_demo.py

import time
import rclpy
from std_msgs.msg import Int32
 
import yasmin
from yasmin import CbState, StateMachine, Blackboard
from yasmin_ros import PublisherState, set_ros_loggers
from yasmin_ros.basic_outcomes import SUCCEED
from yasmin_viewer import YasminViewerPub
 
 
class PublishIntState(PublisherState):
    """
    PublishIntState is a YASMIN ROS publisher state that sends incrementing integers
    to the 'count' topic using std_msgs.msg.Int32 messages.
 
    This state increments a counter on the blackboard and publishes it.
    """
 
    def __init__(self):
        """
        Initializes the PublishIntState with the topic 'count' and a message creation callback.
        """
        super().__init__(Int32, "count", self.create_int_msg)
 
    def create_int_msg(self, blackboard: Blackboard) -> Int32:
        """
        Generates a std_msgs.msg.Int32 message with an incremented counter value.
 
        Args:
            blackboard (Blackboard): The shared data store between states.
 
        Returns:
            Int32: A ROS message containing the updated counter.
        """
        # Get and increment the counter from the blackboard
        counter = blackboard.get("counter")
        counter += 1
        blackboard.set("counter", counter)
 
        # Log the message creation
        yasmin.YASMIN_LOG_INFO(f"Creating message {counter}")
 
        # Create and return the message
        msg = Int32()
        msg.data = counter
        return msg
 
 
def check_count(blackboard: Blackboard) -> str:
    """
    Checks the current counter against a max threshold to determine state transition.
 
    Args:
        blackboard (Blackboard): The shared data store between states.
 
    Returns:
        str: The outcome string ('outcome1' or 'outcome2').
    """
    # Simulate processing time
    time.sleep(1)
 
    # Retrieve the counter and max value from blackboard
    count = blackboard.get("counter")
    max_count = blackboard.get("max_count")
 
    yasmin.YASMIN_LOG_INFO(f"Checking count: {count}")
 
    # Determine and return the outcome based on the counter value
    if count >= max_count:
        return "outcome1"
    else:
        return "outcome2"
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("yasmin_monitor_demo")
    rclpy.init()
 
    # Configure YASMIN to use ROS-based logging
    set_ros_loggers()
 
    # Create the state machine with 'SUCCEED' as the terminal outcome
    sm = StateMachine([SUCCEED])
 
    # Ensure the state machine cancels on shutdown
    def on_shutdown():
        if sm.is_running():
            sm.cancel_state()
 
    rclpy.get_default_context().on_shutdown(on_shutdown)
 
    # Add the publishing state which loops until the condition is met
    sm.add_state(
        "PUBLISHING_INT",
        PublishIntState(),
        {
            SUCCEED: "CHECKING_COUNTS",
        },
    )
 
    # Add the conditional check state
    sm.add_state(
        "CHECKING_COUNTS",
        CbState(["outcome1", "outcome2"], check_count),
        {
            "outcome1": SUCCEED,
            "outcome2": "PUBLISHING_INT",
        },
    )
 
    # Launch YASMIN Viewer publisher for state visualization
    viewer = YasminViewerPub(sm, "YASMIN_PUBLISHER_DEMO")
 
    # Initialize blackboard with counter values
    blackboard = Blackboard()
    blackboard.set("counter", 0)
    blackboard.set("max_count", 10)
 
    # Run the state machine and log the outcome
    try:
        outcome = sm(blackboard)
        yasmin.YASMIN_LOG_INFO(outcome)
    except Exception as e:
        yasmin.YASMIN_LOG_INFO(str(e))
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
 
if __name__ == "__main__":
    main()

Parameters Demo (FSM + ROS 2 Parameters)

Click to expand

ros2 run yasmin_demos parameters_demo.py --ros-args -p max_counter:=5

import time
import rclpy
 
import yasmin
from yasmin import State, Blackboard, StateMachine
from yasmin_ros import set_ros_loggers
from yasmin_ros import GetParametersState
from yasmin_ros.basic_outcomes import SUCCEED, ABORT
from yasmin_viewer import YasminViewerPub
 
 
# Define the FooState class, inheriting from the State class
class FooState(State):
    """
    Represents the Foo state in the state machine.
 
    Attributes:
        counter (int): Counter to track the number of executions of this state.
    """
 
    def __init__(self) -> None:
        """
        Initializes the FooState instance, setting up the outcomes.
 
        Outcomes:
            outcome1: Indicates the state should continue to the Bar state.
            outcome2: Indicates the state should finish execution and return.
        """
        super().__init__(["outcome1", "outcome2"])
        self.counter = 0
 
    def execute(self, blackboard: Blackboard) -> str:
        """
        Executes the logic for the Foo state.
 
        Args:
            blackboard (Blackboard): The shared data structure for states.
 
        Returns:
            str: The outcome of the execution, which can be "outcome1" or "outcome2".
 
        Raises:
            Exception: May raise exceptions related to state execution.
        """
        yasmin.YASMIN_LOG_INFO("Executing state FOO")
        time.sleep(3)  # Simulate work by sleeping
 
        if self.counter < blackboard["max_counter"]:
            self.counter += 1
            blackboard["foo_str"] = f"{blackboard['counter_str']}: {self.counter}"
            return "outcome1"
        else:
            return "outcome2"
 
 
# Define the BarState class, inheriting from the State class
class BarState(State):
    """
    Represents the Bar state in the state machine.
    """
 
    def __init__(self) -> None:
        """
        Initializes the BarState instance, setting up the outcome.
 
        Outcomes:
            outcome3: Indicates the state should transition back to the Foo state.
        """
        super().__init__(outcomes=["outcome3"])
 
    def execute(self, blackboard: Blackboard) -> str:
        """
        Executes the logic for the Bar state.
 
        Args:
            blackboard (Blackboard): The shared data structure for states.
 
        Returns:
            str: The outcome of the execution, which will always be "outcome3".
 
        Raises:
            Exception: May raise exceptions related to state execution.
        """
        yasmin.YASMIN_LOG_INFO("Executing state BAR")
        time.sleep(3)  # Simulate work by sleeping
 
        yasmin.YASMIN_LOG_INFO(blackboard["foo_str"])
        return "outcome3"
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("yasmin_parameters_demo")
 
    # Initialize ROS 2
    rclpy.init()
 
    # Set ROS 2 loggers
    set_ros_loggers()
 
    # Create a finite state machine (FSM)
    sm = StateMachine(outcomes=["outcome4"])
 
    # Add states to the FSM
    sm.add_state(
        "GETTING_PARAMETERS",
        GetParametersState(
            parameters={
                "max_counter": 3,
                "counter_str": "Counter",
            },
        ),
        transitions={
            SUCCEED: "FOO",
            ABORT: "outcome4",
        },
    )
 
    sm.add_state(
        "FOO",
        FooState(),
        transitions={
            "outcome1": "BAR",
            "outcome2": "outcome4",
        },
    )
    sm.add_state(
        "BAR",
        BarState(),
        transitions={
            "outcome3": "FOO",
        },
    )
 
    # Publish FSM information for visualization
    viewer = YasminViewerPub(sm, "YASMIN_PARAMETERS_DEMO")
 
    # Execute the FSM
    try:
        outcome = sm()
        yasmin.YASMIN_LOG_INFO(outcome)
    except KeyboardInterrupt:
        if sm.is_running():
            sm.cancel_state()
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
 
if __name__ == "__main__":
    main()

Nav2 Demo (Hierarchical FSM + ROS 2 Action)

Click to expand

import random
import rclpy
from geometry_msgs.msg import Pose
from nav2_msgs.action import NavigateToPose
 
import yasmin
from yasmin import CbState, Blackboard, StateMachine
from yasmin_ros import ActionState
from yasmin_ros import set_ros_loggers
from yasmin_ros.basic_outcomes import SUCCEED, ABORT, CANCEL
from yasmin_viewer import YasminViewerPub
 
# Constants for state outcomes
HAS_NEXT = "has_next"  
END = "end"  
 
 
class Nav2State(ActionState):
    """
    ActionState for navigating to a specified pose using ROS 2 Navigation.
 
    Attributes:
        None
 
    Methods:
        create_goal_handler(blackboard: Blackboard) -> NavigateToPose.Goal:
            Creates the navigation goal from the blackboard.
    """
 
    def __init__(self) -> None:
        """
        Initializes the Nav2State.
 
        Calls the parent constructor to set up the action with:
        - Action type: NavigateToPose
        - Action name: /navigate_to_pose
        - Callback for goal creation: create_goal_handler
        - Outcomes: None, since it will use default outcomes (SUCCEED, ABORT, CANCEL)
        """
        super().__init__(
            NavigateToPose,  # action type
            "/navigate_to_pose",  # action name
            self.create_goal_handler,  # callback to create the goal
            None,  # outcomes
            None,  # callback to process the response
        )
 
    def create_goal_handler(self, blackboard: Blackboard) -> NavigateToPose.Goal:
        """
        Creates a goal for navigation based on the current pose in the blackboard.
 
        Args:
            blackboard (Blackboard): The blackboard instance holding current state data.
 
        Returns:
            NavigateToPose.Goal: The constructed goal for the navigation action.
        """
        goal = NavigateToPose.Goal()
        goal.pose.pose = blackboard["pose"]
        goal.pose.header.frame_id = "map"  # Set the reference frame to 'map'
        return goal
 
 
def create_waypoints(blackboard: Blackboard) -> str:
    """
    Initializes waypoints in the blackboard for navigation.
 
    Args:
        blackboard (Blackboard): The blackboard instance to store waypoints.
 
    Returns:
        str: Outcome indicating success (SUCCEED).
    """
    blackboard["waypoints"] = {
        "entrance": [1.25, 6.30, -0.78, 0.67],
        "bathroom": [4.89, 1.64, 0.0, 1.0],
        "livingroom": [1.55, 4.03, -0.69, 0.72],
        "kitchen": [3.79, 6.77, 0.99, 0.12],
        "bedroom": [7.50, 4.89, 0.76, 0.65],
    }
    return SUCCEED
 
 
def take_random_waypoint(blackboard: Blackboard) -> str:
    """
    Selects a random set of waypoints from the available waypoints.
 
    Args:
        blackboard (Blackboard): The blackboard instance to store random waypoints.
 
    Returns:
        str: Outcome indicating success (SUCCEED).
    """
    blackboard["random_waypoints"] = random.sample(
        list(blackboard["waypoints"].keys()), blackboard["waypoints_num"]
    )
    return SUCCEED
 
 
def get_next_waypoint(blackboard: Blackboard) -> str:
    """
    Retrieves the next waypoint from the list of random waypoints.
 
    Updates the blackboard with the pose of the next waypoint.
 
    Args:
        blackboard (Blackboard): The blackboard instance holding current state data.
 
    Returns:
        str: Outcome indicating whether there is a next waypoint (HAS_NEXT) or if
             navigation is complete (END).
    """
    if not blackboard["random_waypoints"]:
        return END
 
    wp_name = blackboard["random_waypoints"].pop(0)  # Get the next waypoint name
    wp = blackboard["waypoints"][wp_name]  # Get the waypoint coordinates
 
    pose = Pose()
    pose.position.x = wp[0]
    pose.position.y = wp[1]
    pose.orientation.z = wp[2]
    pose.orientation.w = wp[3]
 
    blackboard["pose"] = pose  # Update blackboard with new pose
    blackboard["text"] = f"I have reached waypoint {wp_name}"
 
    return HAS_NEXT
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("yasmin_nav2_demo")
 
    # Initialize ROS 2
    rclpy.init()
 
    # Set ROS 2 loggers for debugging
    set_ros_loggers()
 
    # Create state machines
    sm = StateMachine(outcomes=[SUCCEED, ABORT, CANCEL])
    nav_sm = StateMachine(outcomes=[SUCCEED, ABORT, CANCEL])
 
    # Add states to the state machine
    sm.add_state(
        "CREATING_WAYPOINTS",
        CbState([SUCCEED], create_waypoints),
        transitions={
            SUCCEED: "TAKING_RANDOM_WAYPOINTS",
        },
    )
    sm.add_state(
        "TAKING_RANDOM_WAYPOINTS",
        CbState([SUCCEED], take_random_waypoint),
        transitions={
            SUCCEED: "NAVIGATING",
        },
    )
 
    nav_sm.add_state(
        "GETTING_NEXT_WAYPOINT",
        CbState([END, HAS_NEXT], get_next_waypoint),
        transitions={
            END: SUCCEED,
            HAS_NEXT: "NAVIGATING",
        },
    )
    nav_sm.add_state(
        "NAVIGATING",
        Nav2State(),
        transitions={
            SUCCEED: "GETTING_NEXT_WAYPOINT",
            CANCEL: CANCEL,
            ABORT: ABORT,
        },
    )
 
    sm.add_state(
        "NAVIGATING",
        nav_sm,
        transitions={
            SUCCEED: SUCCEED,
            CANCEL: CANCEL,
            ABORT: ABORT,
        },
    )
 
    # Publish FSM information for visualization
    viewer = YasminViewerPub(sm, "YASMIN_NAV2_DEMO")
 
    # Execute the state machine
    blackboard = Blackboard()
    blackboard["waypoints_num"] = 2  # Set the number of waypoints to navigate
 
    try:
        outcome = sm(blackboard)  # Run the state machine with the blackboard
        yasmin.YASMIN_LOG_INFO(outcome)
    except KeyboardInterrupt:
        sm.cancel_state()  # Handle manual interruption
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
if __name__ == "__main__":
    main()

Factory Demo (Plugins)

Click to expand

Note: When mixing Python and C++ states in the same state machine, they can communicate through the blackboard, but only with primitive data types: int, float, bool, and string. Complex objects or ROS messages cannot be directly shared between Python and C++ states.

ros2 run yasmin_demos factory_demo.py

<StateMachine outcomes="outcome4">
    <State name="Foo" type="cpp" class="yasmin_demos/FooState">
        <Transition from="outcome1" to="Bar"/>
        <Transition from="outcome2" to="outcome4"/>
    </State>
    <State name="Bar" type="py" module="yasmin_demos.bar_state" class="BarState">
        <Transition from="outcome3" to="Foo"/>
    </State>
</StateMachine>

import os
import rclpy
import yasmin
from yasmin_ros import set_ros_loggers
from yasmin_viewer import YasminViewerPub
from yasmin_factory import YasminFactory
from ament_index_python import get_package_share_directory
 
 
def main() -> None:
    yasmin.YASMIN_LOG_INFO("yasmin_demo")
 
    # Initialize ROS 2
    rclpy.init()
 
    # Set ROS 2 loggers
    set_ros_loggers()
 
    # Create a finite state machine (FSM)
    factory = YasminFactory()
    sm = factory.create_sm_from_file(
        os.path.join(
            get_package_share_directory("yasmin_demos"), "state_machines", "demo_1.xml"
        )
    )
 
    # Publish FSM information for visualization
    viewer = YasminViewerPub(sm, "plugin_demo")
 
    # Execute the FSM
    try:
        outcome = sm()
        yasmin.YASMIN_LOG_INFO(outcome)
    except KeyboardInterrupt:
        if sm.is_running():
            sm.cancel_state()
    finally:
        viewer.cleanup()
        del sm
 
        # Shutdown ROS 2 if it's running
        if rclpy.ok():
            rclpy.shutdown()
 
 
if __name__ == "__main__":
    main()

Cpp

Vanilla Demo

Click to expand

ros2 run yasmin_demos yasmin_demo

#include <chrono>
#include <iostream>
#include <memory>
#include <string>
 
#include "rclcpp/rclcpp.hpp"
#include "yasmin/logs.hpp"
#include "yasmin/state.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_ros/ros_logs.hpp"
#include "yasmin_viewer/yasmin_viewer_pub.hpp"
class FooState : public yasmin::State {
public:
  int counter;
  FooState() : yasmin::State({"outcome1", "outcome2"}), counter(0){};
  std::string
  execute(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) override {
    YASMIN_LOG_INFO("Executing state FOO");
    std::this_thread::sleep_for(std::chrono::seconds(3));
 
    if (this->counter < 3) {
      this->counter += 1;
      blackboard->set<std::string>("foo_str",
                                   "Counter: " + std::to_string(this->counter));
      return "outcome1";
 
    } else {
      return "outcome2";
    }
  };
};
class BarState : public yasmin::State {
public:
  BarState() : yasmin::State({"outcome3"}) {}
  std::string
  execute(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) override {
    YASMIN_LOG_INFO("Executing state BAR");
    std::this_thread::sleep_for(std::chrono::seconds(3));
 
    YASMIN_LOG_INFO(blackboard->get<std::string>("foo_str").c_str());
 
    return "outcome3";
  }
};
 
int main(int argc, char *argv[]) {
  YASMIN_LOG_INFO("yasmin_demo");
  rclcpp::init(argc, argv);
 
  // Set ROS 2 logs
  yasmin_ros::set_ros_loggers();
 
  // Create a state machine
  auto sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{"outcome4"});
 
  // Cancel state machine on ROS 2 shutdown
  rclcpp::on_shutdown([sm]() {
    if (sm->is_running()) {
      sm->cancel_state();
    }
  });
 
  // Add states to the state machine
  sm->add_state("FOO", std::make_shared<FooState>(),
                {
                    {"outcome1", "BAR"},
                    {"outcome2", "outcome4"},
                });
  sm->add_state("BAR", std::make_shared<BarState>(),
                {
                    {"outcome3", "FOO"},
                });
 
  // Publish state machine updates
  yasmin_viewer::YasminViewerPub yasmin_pub(sm, "YASMIN_DEMO");
 
  // Execute the state machine
  try {
    std::string outcome = (*sm.get())();
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  rclcpp::shutdown();
 
  return 0;
}

Blackboard Remapping Demo

Click to expand

ros2 run yasmin_demos remap_demo

#include <chrono>
#include <iostream>
#include <memory>
#include <string>
 
#include "rclcpp/rclcpp.hpp"
#include "yasmin/logs.hpp"
#include "yasmin/state.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_ros/basic_outcomes.hpp"
#include "yasmin_ros/ros_logs.hpp"
#include "yasmin_viewer/yasmin_viewer_pub.hpp"
class FooState : public yasmin::State {
public:
  FooState() : yasmin::State({yasmin_ros::basic_outcomes::SUCCEED}){};
  std::string
  execute(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) override {
    std::string data = blackboard->get<std::string>("foo_data");
    YASMIN_LOG_INFO("%s", data.c_str());
    blackboard->set<std::string>("foo_out_data", data);
    return yasmin_ros::basic_outcomes::SUCCEED;
  };
};
class BarState : public yasmin::State {
public:
  BarState() : yasmin::State({yasmin_ros::basic_outcomes::SUCCEED}) {}
  std::string
  execute(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) override {
    std::string datga = blackboard->get<std::string>("bar_data");
    YASMIN_LOG_INFO("%s", datga.c_str());
    return yasmin_ros::basic_outcomes::SUCCEED;
  }
};
 
int main(int argc, char *argv[]) {
  YASMIN_LOG_INFO("yasmin_remapping_demo");
  rclcpp::init(argc, argv);
 
  // Set ROS 2 logs
  yasmin_ros::set_ros_loggers();
 
  // Create blackboard
  auto blackboard = std::make_shared<yasmin::blackboard::Blackboard>();
  blackboard->set<std::string>("msg1", "test1");
  blackboard->set<std::string>("msg2", "test2");
 
  // Create a state machine
  auto sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{yasmin_ros::basic_outcomes::SUCCEED});
 
  // Cancel state machine on ROS 2 shutdown
  rclcpp::on_shutdown([sm]() {
    if (sm->is_running()) {
      sm->cancel_state();
    }
  });
 
  // Add states to the state machine
  sm->add_state("STATE1", std::make_shared<FooState>(),
                {
                    {yasmin_ros::basic_outcomes::SUCCEED, "STATE2"},
                },
                {
                    {"foo_data", "msg1"},
                });
  sm->add_state("STATE2", std::make_shared<FooState>(),
                {
                    {yasmin_ros::basic_outcomes::SUCCEED, "STATE3"},
                },
                {
                    {"foo_data", "msg2"},
                });
  sm->add_state("STATE3", std::make_shared<BarState>(),
                {
                    {yasmin_ros::basic_outcomes::SUCCEED,
                     yasmin_ros::basic_outcomes::SUCCEED},
                },
                {
                    {"bar_data", "foo_out_data"},
                });
 
  // Publish state machine updates
  yasmin_viewer::YasminViewerPub yasmin_pub(sm, "YASMIN_REMAPPING_DEMO");
 
  // Execute the state machine
  try {
    std::string outcome = (*sm.get())(blackboard);
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  rclcpp::shutdown();
 
  return 0;
}

Concurrence Demo

Click to expand

ros2 run yasmin_demos concurrence_demo

#include <chrono>
#include <iostream>
#include <memory>
#include <string>
 
#include "rclcpp/rclcpp.hpp"
#include "yasmin/concurrence.hpp"
#include "yasmin/logs.hpp"
#include "yasmin/state.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_ros/ros_logs.hpp"
#include "yasmin_viewer/yasmin_viewer_pub.hpp"
class FooState : public yasmin::State {
public:
  int counter;
  FooState()
      : yasmin::State({"outcome1", "outcome2", "outcome3"}), counter(0){};
  std::string
  execute(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) override {
    YASMIN_LOG_INFO("Executing state FOO");
    std::this_thread::sleep_for(std::chrono::seconds(2));
 
    std::string outcome;
 
    blackboard->set<std::string>("foo_str",
                                 "Counter: " + std::to_string(this->counter));
 
    if (this->counter < 3) {
      outcome = "outcome1";
    } else if (this->counter < 5) {
      outcome = "outcome2";
    } else {
      outcome = "outcome3";
    }
 
    YASMIN_LOG_INFO("Finishing state FOO");
    this->counter += 1;
    return outcome;
  };
};
class BarState : public yasmin::State {
public:
  BarState() : yasmin::State({"outcome3"}) {}
  std::string
  execute(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) override {
    YASMIN_LOG_INFO("Executing state BAR");
    std::this_thread::sleep_for(std::chrono::seconds(4));
 
    if (blackboard->contains("foo_str")) {
      YASMIN_LOG_INFO(blackboard->get<std::string>("foo_str").c_str());
    } else {
      YASMIN_LOG_INFO("blackboard does not yet contains 'foo_str'");
    }
 
    YASMIN_LOG_INFO("Finishing state BAR");
 
    return "outcome3";
  }
};
 
int main(int argc, char *argv[]) {
  YASMIN_LOG_INFO("yasmin_concurrence_demo");
  rclcpp::init(argc, argv);
 
  // Set ROS 2 logs
  yasmin_ros::set_ros_loggers();
 
  // Create a state machine
  auto sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{"outcome4"});
 
  // Cancel state machine on ROS 2 shutdown
  rclcpp::on_shutdown([sm]() {
    if (sm->is_running()) {
      sm->cancel_state();
    }
  });
 
  // Create states to run concurrently
  auto foo_state = std::make_shared<FooState>();
  auto bar_state = std::make_shared<BarState>();
 
  // Create concurrent state
  auto concurrent_state = std::make_shared<yasmin::Concurrence>(
      std::map<std::string, std::shared_ptr<yasmin::State>>{{"FOO", foo_state},
                                                            {"BAR", bar_state}},
      "defaulted",
      yasmin::Concurrence::OutcomeMap{
          {"outcome1",
           yasmin::Concurrence::StateOutcomeMap{{"FOO", "outcome1"},
                                                {"BAR", "outcome3"}}},
          {"outcome2", yasmin::Concurrence::StateOutcomeMap{
                           {"FOO", "outcome2"}, {"BAR", "outcome3"}}}});
 
  // Add concurrent state to the state machine
  sm->add_state("CONCURRENCE", concurrent_state,
                {
                    {"outcome1", "CONCURRENCE"},
                    {"outcome2", "CONCURRENCE"},
                    {"defaulted", "outcome4"},
                });
 
  // Publish state machine updates
  yasmin_viewer::YasminViewerPub yasmin_pub(sm, "YASMIN_CONCURRENCE_DEMO");
 
  // Execute the state machine
  try {
    std::string outcome = (*sm.get())();
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  rclcpp::shutdown();
 
  return 0;
}

Service Demo (FSM + ROS 2 Service Client)

Click to expand

ros2 run yasmin_demos add_two_ints_server

ros2 run yasmin_demos service_client_demo

#include <iostream>
#include <memory>
#include <string>
 
#include "example_interfaces/srv/add_two_ints.hpp"
#include "rclcpp/rclcpp.hpp"
 
#include "yasmin/cb_state.hpp"
#include "yasmin/logs.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_ros/basic_outcomes.hpp"
#include "yasmin_ros/ros_logs.hpp"
#include "yasmin_ros/service_state.hpp"
#include "yasmin_viewer/yasmin_viewer_pub.hpp"
 
using std::placeholders::_1;
using std::placeholders::_2;
std::string
set_ints(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
  blackboard->set<int>("a", 10);
  blackboard->set<int>("b", 5);
  return yasmin_ros::basic_outcomes::SUCCEED;
}
std::string
print_sum(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
  std::stringstream ss;
  ss << "Sum: " << blackboard->get<int>("sum");
  YASMIN_LOG_INFO(ss.str().c_str());
  return yasmin_ros::basic_outcomes::SUCCEED;
}
class AddTwoIntsState
    : public yasmin_ros::ServiceState<example_interfaces::srv::AddTwoInts> {
public:
  AddTwoIntsState()
      : yasmin_ros::ServiceState<example_interfaces::srv::AddTwoInts>(
            "/add_two_ints",
            std::bind(&AddTwoIntsState::create_request_handler, this, _1),
            {"outcome1"},
            std::bind(&AddTwoIntsState::response_handler, this, _1, _2)){};
  example_interfaces::srv::AddTwoInts::Request::SharedPtr
  create_request_handler(
      std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
 
    auto request =
        std::make_shared<example_interfaces::srv::AddTwoInts::Request>();
    request->a = blackboard->get<int>("a");
    request->b = blackboard->get<int>("b");
    return request;
  };
  std::string response_handler(
      std::shared_ptr<yasmin::blackboard::Blackboard> blackboard,
      example_interfaces::srv::AddTwoInts::Response::SharedPtr response) {
 
    blackboard->set<int>("sum", response->sum);
    return "outcome1";
  };
};
 
int main(int argc, char *argv[]) {
  YASMIN_LOG_INFO("yasmin_service_client_demo");
  rclcpp::init(argc, argv);
 
  // Set up ROS 2 logging.
  yasmin_ros::set_ros_loggers();
 
  // Create a state machine with a specified outcome.
  auto sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{"outcome4"});
 
  // Cancel the state machine on ROS 2 shutdown.
  rclcpp::on_shutdown([sm]() {
    if (sm->is_running()) {
      sm->cancel_state();
    }
  });
 
  // Add states to the state machine.
  sm->add_state("SETTING_INTS",
                std::make_shared<yasmin::CbState>(
                    std::initializer_list<std::string>{
                        yasmin_ros::basic_outcomes::SUCCEED},
                    set_ints),
                {
                    {yasmin_ros::basic_outcomes::SUCCEED, "ADD_TWO_INTS"},
                });
  sm->add_state("ADD_TWO_INTS", std::make_shared<AddTwoIntsState>(),
                {
                    {"outcome1", "PRINTING_SUM"},
                    {yasmin_ros::basic_outcomes::SUCCEED, "outcome4"},
                    {yasmin_ros::basic_outcomes::ABORT, "outcome4"},
                });
  sm->add_state("PRINTING_SUM",
                std::make_shared<yasmin::CbState>(
                    std::initializer_list<std::string>{
                        yasmin_ros::basic_outcomes::SUCCEED},
                    print_sum),
                {
                    {yasmin_ros::basic_outcomes::SUCCEED, "outcome4"},
                });
 
  // Publish state machine visualization.
  yasmin_viewer::YasminViewerPub yasmin_pub(sm, "YASMIN_SERVICE_CLIENT_DEMO");
 
  // Execute the state machine.
  try {
    std::string outcome = (*sm.get())();
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  rclcpp::shutdown();
 
  return 0;
}

Action Demo (FSM + ROS 2 Action)

Click to expand

ros2 run yasmin_demos fibonacci_action_server

ros2 run yasmin_demos action_client_demo

#include <iostream>
#include <memory>
#include <string>
 
#include "example_interfaces/action/fibonacci.hpp"
 
#include "yasmin/cb_state.hpp"
#include "yasmin/logs.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_ros/action_state.hpp"
#include "yasmin_ros/basic_outcomes.hpp"
#include "yasmin_ros/ros_logs.hpp"
#include "yasmin_ros/yasmin_node.hpp"
#include "yasmin_viewer/yasmin_viewer_pub.hpp"
 
using std::placeholders::_1;
using std::placeholders::_2;
using Fibonacci = example_interfaces::action::Fibonacci;
std::string
print_result(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
 
  auto fibo_res = blackboard->get<std::vector<int>>("fibo_res");
 
  std::stringstream ss;
  ss << "Result: [";
  for (size_t i = 0; i < fibo_res.size(); i++) {
    ss << fibo_res[i];
    if (i < fibo_res.size() - 1) {
      ss << ", ";
    }
  }
  ss << "]";
 
  YASMIN_LOG_INFO(ss.str().c_str());
 
  return yasmin_ros::basic_outcomes::SUCCEED;
}
class FibonacciState : public yasmin_ros::ActionState<Fibonacci> {
 
public:
  FibonacciState()
      : yasmin_ros::ActionState<Fibonacci>(
            "/fibonacci",
            std::bind(&FibonacciState::create_goal_handler, this, _1),
            std::bind(&FibonacciState::response_handler, this, _1, _2),
            std::bind(&FibonacciState::print_feedback, this, _1, _2)){};
  Fibonacci::Goal create_goal_handler(
      std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
 
    auto goal = Fibonacci::Goal();
    goal.order = blackboard->get<int>("n");
    return goal;
  };
  std::string
  response_handler(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard,
                   Fibonacci::Result::SharedPtr response) {
 
    blackboard->set<std::vector<int>>("fibo_res", response->sequence);
    return yasmin_ros::basic_outcomes::SUCCEED;
  };
  void
  print_feedback(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard,
                 std::shared_ptr<const Fibonacci::Feedback> feedback) {
    (void)blackboard;
 
    std::stringstream ss;
    ss << "Received feedback: [";
    for (size_t i = 0; i < feedback->sequence.size(); i++) {
      ss << feedback->sequence[i];
      if (i < feedback->sequence.size() - 1) {
        ss << ", ";
      }
    }
    ss << "]";
 
    YASMIN_LOG_INFO(ss.str().c_str());
  };
};
 
int main(int argc, char *argv[]) {
 
  YASMIN_LOG_INFO("yasmin_action_client_demo");
  rclcpp::init(argc, argv);
 
  // Set ROS 2 logging
  yasmin_ros::set_ros_loggers();
 
  // Create the state machine
  auto sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{"outcome4"});
 
  // Cancel state machine on ROS 2 shutdown
  rclcpp::on_shutdown([sm]() {
    if (sm->is_running()) {
      sm->cancel_state();
    }
  });
 
  // Add states to the state machine
  sm->add_state("CALLING_FIBONACCI", std::make_shared<FibonacciState>(),
                {
                    {yasmin_ros::basic_outcomes::SUCCEED, "PRINTING_RESULT"},
                    {yasmin_ros::basic_outcomes::CANCEL, "outcome4"},
                    {yasmin_ros::basic_outcomes::ABORT, "outcome4"},
                });
  sm->add_state("PRINTING_RESULT",
                std::make_shared<yasmin::CbState>(
                    std::initializer_list<std::string>{
                        yasmin_ros::basic_outcomes::SUCCEED},
                    print_result),
                {
                    {yasmin_ros::basic_outcomes::SUCCEED, "outcome4"},
                });
 
  // Publisher for visualizing the state machine
  yasmin_viewer::YasminViewerPub yasmin_pub(sm, "YASMIN_ACTION_CLIENT_DEMO");
 
  // Create an initial blackboard and set the Fibonacci order
  std::shared_ptr<yasmin::blackboard::Blackboard> blackboard =
      std::make_shared<yasmin::blackboard::Blackboard>();
  blackboard->set<int>("n", 10);
 
  // Execute the state machine
  try {
    std::string outcome = (*sm.get())(blackboard);
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  rclcpp::shutdown();
 
  return 0;
}

Monitor Demo (FSM + ROS 2 Subscriber)

Click to expand

ros2 run yasmin_demos monitor_demo

#include <iostream>
#include <memory>
#include <string>
 
#include "nav_msgs/msg/odometry.hpp"
#include "rclcpp/rclcpp.hpp"
 
#include "yasmin/logs.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_ros/basic_outcomes.hpp"
#include "yasmin_ros/monitor_state.hpp"
#include "yasmin_ros/ros_logs.hpp"
#include "yasmin_viewer/yasmin_viewer_pub.hpp"
 
using std::placeholders::_1;
using std::placeholders::_2;
class PrintOdometryState
    : public yasmin_ros::MonitorState<nav_msgs::msg::Odometry> {
 
public:
  int times;
  PrintOdometryState(int times)
      : yasmin_ros::MonitorState<nav_msgs::msg::Odometry>(
            "odom",                   // topic name
            {"outcome1", "outcome2"}, // possible outcomes
            std::bind(&PrintOdometryState::monitor_handler, this, _1,
                      _2), // monitor handler callback
            10,            // QoS for the topic subscription
            10,            // queue size for the callback
            10             // timeout for receiving messages
        ) {
    this->times = times;
  };
  std::string
  monitor_handler(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard,
                  std::shared_ptr<nav_msgs::msg::Odometry> msg) {
 
    (void)blackboard; // blackboard is not used in this implementation
 
    YASMIN_LOG_INFO("x: %f", msg->pose.pose.position.x);
    YASMIN_LOG_INFO("y: %f", msg->pose.pose.position.y);
    YASMIN_LOG_INFO("z: %f", msg->pose.pose.position.z);
 
    this->times--;
 
    // Transition based on remaining times
    if (this->times <= 0) {
      return "outcome2";
    }
 
    return "outcome1";
  };
};
 
int main(int argc, char *argv[]) {
 
  YASMIN_LOG_INFO("yasmin_monitor_demo");
  rclcpp::init(argc, argv);
 
  // Set up ROS 2 loggers
  yasmin_ros::set_ros_loggers();
 
  // Create a state machine with a final outcome
  auto sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{"outcome4"});
 
  // Cancel state machine on ROS 2 shutdown
  rclcpp::on_shutdown([sm]() {
    if (sm->is_running()) {
      sm->cancel_state();
    }
  });
 
  // Add states to the state machine
  sm->add_state(
      "PRINTING_ODOM", std::make_shared<PrintOdometryState>(5),
      {
          {"outcome1",
           "PRINTING_ODOM"},        // Transition back to itself on outcome1
          {"outcome2", "outcome4"}, // Transition to outcome4 on outcome2
          {yasmin_ros::basic_outcomes::TIMEOUT,
           "outcome4"}, // Timeout transition
      });
 
  // Publisher for visualizing the state machine's status
  yasmin_viewer::YasminViewerPub yasmin_pub(sm, "YASMIN_MONITOR_DEMO");
 
  // Execute the state machine
  try {
    std::string outcome = (*sm.get())();
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  rclcpp::shutdown();
 
  return 0;
}

Publisher Demo (FSM + ROS 2 Publisher)

Click to expand

ros2 run yasmin_demos publisher_demo

#include <iostream>
#include <memory>
#include <string>
 
#include "rclcpp/rclcpp.hpp"
#include "std_msgs/msg/int32.hpp"
 
#include "yasmin/cb_state.hpp"
#include "yasmin/logs.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_ros/basic_outcomes.hpp"
#include "yasmin_ros/publisher_state.hpp"
#include "yasmin_ros/ros_logs.hpp"
#include "yasmin_viewer/yasmin_viewer_pub.hpp"
 
using std::placeholders::_1;
using std::placeholders::_2;
class PublishIntState
    : public yasmin_ros::PublisherState<std_msgs::msg::Int32> {
 
public:
  PublishIntState()
      : yasmin_ros::PublisherState<std_msgs::msg::Int32>(
            "count", // topic name
            std::bind(&PublishIntState::create_int_msg, this,
                      _1) // create msg handler callback
        ){};
  std_msgs::msg::Int32
  create_int_msg(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
 
    int counter = blackboard->get<int>("counter");
    counter++;
    blackboard->set<int>("counter", counter);
 
    YASMIN_LOG_INFO("Creating message %d", counter);
    std_msgs::msg::Int32 msg;
    msg.data = counter;
    return msg;
  };
};
std::string
check_count(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
 
  // Sleep for 1 second to simulate some processing time
  rclcpp::sleep_for(std::chrono::seconds(1));
  YASMIN_LOG_INFO("Checking count: %d", blackboard->get<int>("counter"));
 
  if (blackboard->get<int>("counter") >= blackboard->get<int>("max_count")) {
    return "outcome1";
  } else {
    return "outcome2";
  }
}
 
int main(int argc, char *argv[]) {
 
  YASMIN_LOG_INFO("yasmin_publisher_demo");
  rclcpp::init(argc, argv);
 
  // Set up ROS 2 loggers
  yasmin_ros::set_ros_loggers();
 
  // Create a state machine with a final outcome
  auto sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{yasmin_ros::basic_outcomes::SUCCEED});
 
  // Cancel state machine on ROS 2 shutdown
  rclcpp::on_shutdown([sm]() {
    if (sm->is_running()) {
      sm->cancel_state();
    }
  });
 
  // Add states to the state machine
  sm->add_state("PUBLISHING_INT", std::make_shared<PublishIntState>(),
                {
                    {yasmin_ros::basic_outcomes::SUCCEED,
                     "CHECKINNG_COUNTS"}, // Transition back to itself
                });
  sm->add_state("CHECKINNG_COUNTS",
                std::make_shared<yasmin::CbState>(
                    std::initializer_list<std::string>{"outcome1", "outcome2"},
                    check_count),
                {{"outcome1", yasmin_ros::basic_outcomes::SUCCEED},
                 {"outcome2", "PUBLISHING_INT"}});
 
  // Publisher for visualizing the state machine's status
  yasmin_viewer::YasminViewerPub yasmin_pub(sm, "YASMIN_PUBLISHER_DEMO");
 
  // Execute the state machine
  std::shared_ptr<yasmin::blackboard::Blackboard> blackboard =
      std::make_shared<yasmin::blackboard::Blackboard>();
  blackboard->set<int>("counter", 0);
  blackboard->set<int>("max_count", 10);
  try {
    std::string outcome = (*sm.get())(blackboard);
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  rclcpp::shutdown();
 
  return 0;
}

Parameters Demo (FSM + ROS 2 Parameters)

Click to expand

ros2 run yasmin_demos parameters_demo --ros-args -p max_counter:=5

#include <chrono>
#include <iostream>
#include <memory>
#include <string>
 
#include "rclcpp/rclcpp.hpp"
#include "yasmin/logs.hpp"
#include "yasmin/state.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_ros/basic_outcomes.hpp"
#include "yasmin_ros/get_parameters_state.hpp"
#include "yasmin_ros/ros_logs.hpp"
#include "yasmin_viewer/yasmin_viewer_pub.hpp"
class FooState : public yasmin::State {
public:
  int counter;
  FooState() : yasmin::State({"outcome1", "outcome2"}), counter(0){};
  std::string
  execute(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) override {
    YASMIN_LOG_INFO("Executing state FOO");
    std::this_thread::sleep_for(std::chrono::seconds(3));
 
    if (this->counter < blackboard->get<int>("max_counter")) {
      this->counter += 1;
      blackboard->set<std::string>("foo_str",
                                   blackboard->get<std::string>("counter_str") +
                                       ": " + std::to_string(this->counter));
      return "outcome1";
 
    } else {
      return "outcome2";
    }
  };
};
class BarState : public yasmin::State {
public:
  BarState() : yasmin::State({"outcome3"}) {}
  std::string
  execute(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) override {
    YASMIN_LOG_INFO("Executing state BAR");
    std::this_thread::sleep_for(std::chrono::seconds(3));
 
    YASMIN_LOG_INFO(blackboard->get<std::string>("foo_str").c_str());
 
    return "outcome3";
  }
};
 
int main(int argc, char *argv[]) {
  YASMIN_LOG_INFO("yasmin_parameters_demo");
  rclcpp::init(argc, argv);
 
  // Set ROS 2 logs
  yasmin_ros::set_ros_loggers();
 
  // Create a state machine
  auto sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{"outcome4"});
 
  // Cancel state machine on ROS 2 shutdown
  rclcpp::on_shutdown([sm]() {
    if (sm->is_running()) {
      sm->cancel_state();
    }
  });
 
  // Add states to the state machine
  sm->add_state("GETTING_PARAMETERS",
                std::make_shared<yasmin_ros::GetParametersState>(
                    std::map<std::string, std::any>{
                        {"max_counter", 3},
                        {"counter_str", std::string("Counter")},
                    }),
                {
                    {yasmin_ros::basic_outcomes::SUCCEED, "FOO"},
                    {yasmin_ros::basic_outcomes::ABORT, "outcome4"},
                });
  sm->add_state("FOO", std::make_shared<FooState>(),
                {
                    {"outcome1", "BAR"},
                    {"outcome2", "outcome4"},
                });
  sm->add_state("BAR", std::make_shared<BarState>(),
                {
                    {"outcome3", "FOO"},
                });
 
  // Publish state machine updates
  yasmin_viewer::YasminViewerPub yasmin_pub(sm, "YASMIN_PARAMETERS_DEMO");
 
  // Execute the state machine
  try {
    std::string outcome = (*sm.get())();
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  rclcpp::shutdown();
 
  return 0;
}

Nav2 Demo (Hierarchical FSM + ROS 2 Action)

Click to expand

#include <algorithm>
#include <iostream>
#include <map>
#include <memory>
#include <random>
#include <string>
#include <vector>
 
#include "geometry_msgs/msg/pose.hpp"
#include "nav2_msgs/action/navigate_to_pose.hpp"
 
#include "yasmin/blackboard/blackboard.hpp"
#include "yasmin/cb_state.hpp"
#include "yasmin/logs.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_ros/action_state.hpp"
#include "yasmin_ros/basic_outcomes.hpp"
#include "yasmin_ros/ros_logs.hpp"
#include "yasmin_viewer/yasmin_viewer_pub.hpp"
 
using std::placeholders::_1;
using std::placeholders::_2;
using NavigateToPose = nav2_msgs::action::NavigateToPose;
using Pose = geometry_msgs::msg::Pose;
 
// Constants for state outcomes
const std::string HAS_NEXT = "has_next"; 
const std::string END = "end";           
class Nav2State : public yasmin_ros::ActionState<NavigateToPose> {
public:
  Nav2State()
      : yasmin_ros::ActionState<NavigateToPose>(
            "/navigate_to_pose",
            std::bind(&Nav2State::create_goal_handler, this, _1)) {}
  NavigateToPose::Goal create_goal_handler(
      std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
    NavigateToPose::Goal goal;
    goal.pose.pose = blackboard->get<Pose>("pose");
    goal.pose.header.frame_id = "map"; // Set the reference frame to 'map'
    return goal;
  }
};
std::string
create_waypoints(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
  std::map<std::string, std::vector<double>> waypoints = {
      {"entrance", {1.25, 6.30, -0.78, 0.67}},
      {"bathroom", {4.89, 1.64, 0.0, 1.0}},
      {"livingroom", {1.55, 4.03, -0.69, 0.72}},
      {"kitchen", {3.79, 6.77, 0.99, 0.12}},
      {"bedroom", {7.50, 4.89, 0.76, 0.65}}};
  blackboard->set<std::map<std::string, std::vector<double>>>("waypoints",
                                                              waypoints);
  return yasmin_ros::basic_outcomes::SUCCEED;
}
std::string take_random_waypoint(
    std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
  auto waypoints =
      blackboard->get<std::map<std::string, std::vector<double>>>("waypoints");
  int waypoints_num = blackboard->get<int>("waypoints_num");
 
  std::vector<std::string> waypoint_names;
  for (const auto &pair : waypoints) {
    waypoint_names.push_back(pair.first);
  }
 
  // Randomly select waypoints_num waypoints
  std::random_device rd;
  std::mt19937 g(rd());
  std::shuffle(waypoint_names.begin(), waypoint_names.end(), g);
  std::vector<std::string> random_waypoints(
      waypoint_names.begin(), waypoint_names.begin() + waypoints_num);
 
  blackboard->set<std::vector<std::string>>("random_waypoints",
                                            random_waypoints);
  return yasmin_ros::basic_outcomes::SUCCEED;
}
std::string
get_next_waypoint(std::shared_ptr<yasmin::blackboard::Blackboard> blackboard) {
  auto random_waypoints =
      blackboard->get<std::vector<std::string>>("random_waypoints");
  auto waypoints =
      blackboard->get<std::map<std::string, std::vector<double>>>("waypoints");
 
  if (random_waypoints.empty()) {
    return END;
  }
 
  std::string wp_name = random_waypoints.back();
  random_waypoints.pop_back();
  blackboard->set<std::vector<std::string>>("random_waypoints",
                                            random_waypoints);
 
  auto wp = waypoints.at(wp_name);
 
  Pose pose;
  pose.position.x = wp[0];
  pose.position.y = wp[1];
  pose.orientation.z = wp[2];
  pose.orientation.w = wp[3];
 
  blackboard->set<Pose>("pose", pose);
  blackboard->set<std::string>("text", "I have reached waypoint " + wp_name);
 
  return HAS_NEXT;
}
 
int main(int argc, char *argv[]) {
  YASMIN_LOG_INFO("yasmin_nav2_demo");
  rclcpp::init(argc, argv);
 
  // Set ROS 2 logs
  yasmin_ros::set_ros_loggers();
 
  // Create state machines
  auto sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{yasmin_ros::basic_outcomes::SUCCEED,
                                         yasmin_ros::basic_outcomes::ABORT,
                                         yasmin_ros::basic_outcomes::CANCEL});
  auto nav_sm = std::make_shared<yasmin::StateMachine>(
      std::initializer_list<std::string>{yasmin_ros::basic_outcomes::SUCCEED,
                                         yasmin_ros::basic_outcomes::ABORT,
                                         yasmin_ros::basic_outcomes::CANCEL});
 
  // Cancel state machines on ROS 2 shutdown
  rclcpp::on_shutdown([sm, nav_sm]() {
    if (sm->is_running()) {
      sm->cancel_state();
    }
    if (nav_sm->is_running()) {
      nav_sm->cancel_state();
    }
  });
 
  // Add states to the state machine
  sm->add_state(
      "CREATING_WAYPOINTS",
      std::make_shared<yasmin::CbState>(
          std::initializer_list<std::string>{
              yasmin_ros::basic_outcomes::SUCCEED},
          create_waypoints),
      std::map<std::string, std::string>{
          {yasmin_ros::basic_outcomes::SUCCEED, "TAKING_RANDOM_WAYPOINTS"}});
  sm->add_state("TAKING_RANDOM_WAYPOINTS",
                std::make_shared<yasmin::CbState>(
                    std::initializer_list<std::string>{
                        yasmin_ros::basic_outcomes::SUCCEED},
                    take_random_waypoint),
                std::map<std::string, std::string>{
                    {yasmin_ros::basic_outcomes::SUCCEED, "NAVIGATING"}});
 
  nav_sm->add_state(
      "GETTING_NEXT_WAYPOINT",
      std::make_shared<yasmin::CbState>(
          std::initializer_list<std::string>{END, HAS_NEXT}, get_next_waypoint),
      std::map<std::string, std::string>{
          {END, yasmin_ros::basic_outcomes::SUCCEED},
          {HAS_NEXT, "NAVIGATING"}});
  nav_sm->add_state(
      "NAVIGATING", std::make_shared<Nav2State>(),
      std::map<std::string, std::string>{
          {yasmin_ros::basic_outcomes::SUCCEED, "GETTING_NEXT_WAYPOINT"},
          {yasmin_ros::basic_outcomes::CANCEL,
           yasmin_ros::basic_outcomes::CANCEL},
          {yasmin_ros::basic_outcomes::ABORT,
           yasmin_ros::basic_outcomes::ABORT}});
 
  sm->add_state(
      "NAVIGATING", nav_sm,
      std::map<std::string, std::string>{{yasmin_ros::basic_outcomes::SUCCEED,
                                          yasmin_ros::basic_outcomes::SUCCEED},
                                         {yasmin_ros::basic_outcomes::CANCEL,
                                          yasmin_ros::basic_outcomes::CANCEL},
                                         {yasmin_ros::basic_outcomes::ABORT,
                                          yasmin_ros::basic_outcomes::ABORT}});
 
  // Publish FSM information for visualization
  yasmin_viewer::YasminViewerPub yasmin_pub(sm, "YASMIN_NAV2_DEMO");
 
  // Execute the state machine
  auto blackboard = std::make_shared<yasmin::blackboard::Blackboard>();
  blackboard->set<int>("waypoints_num",
                       2); // Set the number of waypoints to navigate
 
  try {
    std::string outcome = (*sm.get())(blackboard);
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  rclcpp::shutdown();
 
  return 0;
}

Factory Demo (Plugins)

Click to expand

Note: When mixing Python and C++ states in the same state machine, they can communicate through the blackboard, but only with primitive data types: int, float, bool, and string. Complex objects or ROS messages cannot be directly shared between Python and C++ states.

ros2 run yasmin_demos factory_demo

<StateMachine outcomes="outcome4">
    <State name="Foo" type="py" module="yasmin_demos.foo_state" class="FooState">
        <Transition from="outcome1" to="Bar"/>
        <Transition from="outcome2" to="outcome4"/>
    </State>
    <State name="Bar" type="cpp" class="yasmin_demos/BarState">
        <Transition from="outcome3" to="Foo"/>
    </State>
</StateMachine>

#include <iostream>
#include <memory>
#include <string>
 
#include "ament_index_cpp/get_package_share_directory.hpp"
#include "rclcpp/rclcpp.hpp"
#include "yasmin/state_machine.hpp"
#include "yasmin_factory/yasmin_factory.hpp"
#include "yasmin_ros/ros_logs.hpp"
 
int main(int argc, char *argv[]) {
  YASMIN_LOG_INFO("yasmin_factory_demo");
  rclcpp::init(argc, argv);
 
  // Set up ROS 2 loggers
  yasmin_ros::set_ros_loggers();
 
  std::string outcome;
 
  // Create the factory in a scope
  yasmin_factory::YasminFactory factory;
 
  // Load state machine from XML file
  std::string xml_file =
      ament_index_cpp::get_package_share_directory("yasmin_demos") +
      "/state_machines/demo_2.xml";
 
  // Create the state machine from the XML file
  auto sm = factory.create_sm_from_file(xml_file);
 
  // Execute the state machine
  try {
    std::string outcome = (*sm.get())();
    YASMIN_LOG_INFO(outcome.c_str());
  } catch (const std::exception &e) {
    YASMIN_LOG_WARN(e.what());
  }
 
  // Shutdown ROS 2
  rclcpp::shutdown();
  return 0;
}

YASMIN Editor

The YASMIN Editor is a graphical user interface application for building YASMIN state machines using state plugins. It enables intuitive creation of state machines through drag-and-drop functionality, allowing you to:

Load Python and C++ states
Load XML state machines
Define transitions between states
Create outcomes
Visualize state machine structure

State machines can be exported and saved in XML format for reuse and sharing.

YASMIN Editor Interface

Getting Started

ros2 run yasmin_editor yasmin_editor

YASMIN Viewer

The YASMIN Viewer provides a convenient way to monitor YASMIN's Finite State Machines (FSM). It is built using Flask and ReactJS and includes a filter to focus on a single FSM at a time.

YASMIN Viewer

Getting Started

ros2 run yasmin_viewer yasmin_viewer_node

Once started, open http://localhost:5000/ in your browser to view your state machines.

Custom host and port

You can specify a custom host and port by using the following command:

ros2 run yasmin_viewer yasmin_viewer_node --ros-args -p host:=127.0.0.1 -p port:=5032

After running the command, access your state machines at http://127.0.0.1:5032/.

Citations

@InProceedings{10.1007/978-3-031-21062-4_43,
author="Gonz{\'a}lez-Santamarta, Miguel {\'A}.
and Rodr{\'i}guez-Lera, Francisco J.
and Matell{\'a}n-Olivera, Vicente
and Fern{\'a}ndez-Llamas, Camino",
editor="Tardioli, Danilo
and Matell{\'a}n, Vicente
and Heredia, Guillermo
and Silva, Manuel F.
and Marques, Lino",
title="YASMIN: Yet Another State MachINe",
booktitle="ROBOT2022: Fifth Iberian Robotics Conference",
year="2023",
publisher="Springer International Publishing",
address="Cham",
pages="528--539",
abstract="State machines are a common mechanism for defining behaviors in robots where each behavior is based on identifiable stages. There are several libraries available for easing the implementation of state machines in ROS 1, however, the community was focused on SMACH or SMACC. Although these tools are still predominant, there are fewer alternatives for ROS 2. Besides, Behavior Trees are spreading fast, but there is a niche for using State Machines. Here, YASMIN is presented as yet another library specifically designed for ROS 2 for easing the design of robotic behaviors using state machines. It is available in C++ and Python, and provides some default states to speed up the development, in addition to a web viewer for monitoring the execution of the system and helping in the debugging.",
isbn="978-3-031-21062-4"
}

@misc{yasmin,
  doi = {10.48550/ARXIV.2205.13284},
  url = {https://arxiv.org/abs/2205.13284},
  author = {González-Santamarta, Miguel Ángel and Rodríguez-Lera, Francisco Javier and Llamas, Camino Fernández and Rico, Francisco Martín and Olivera, Vicente Matellán},
  keywords = {Robotics (cs.RO), FOS: Computer and information sciences, FOS: Computer and information sciences},
  title = {YASMIN: Yet Another State MachINe library for ROS 2},
  publisher = {arXiv},
  year = {2022},
  copyright = {Creative Commons Attribution Non Commercial No Derivatives 4.0 International}
}

Table of Contents

Key Features

Installation

Debian Packages

Building from Source

Docker

Demos

Python

Vanilla Demo (FSM)

Blackboard Remapping Demo

Concurrence Demo

Service Demo (FSM + ROS 2 Service Client)

Action Demo (FSM + ROS 2 Action)

Monitor Demo (FSM + ROS 2 Subscriber)

Publisher Demo (FSM + ROS 2 Publisher)

Parameters Demo (FSM + ROS 2 Parameters)

Nav2 Demo (Hierarchical FSM + ROS 2 Action)

Factory Demo (Plugins)

Cpp

Vanilla Demo

Blackboard Remapping Demo

Concurrence Demo

Service Demo (FSM + ROS 2 Service Client)

Action Demo (FSM + ROS 2 Action)

Monitor Demo (FSM + ROS 2 Subscriber)

Publisher Demo (FSM + ROS 2 Publisher)

Parameters Demo (FSM + ROS 2 Parameters)

Nav2 Demo (Hierarchical FSM + ROS 2 Action)

Factory Demo (Plugins)

YASMIN Editor

Getting Started

YASMIN Viewer

Getting Started

Custom host and port

Citations